Maintaining mobility improvement and short channel control as microelectronic device dimensions continue to scale provides a challenge in device fabrication. In particular, during design and manufacture of metal-oxide-semiconductor (MOS) transistor semiconductor devices, such as those used in complementary metal-oxide-semiconductor (CMOS) devices, it is often desired to increase movement of electrons (carriers) in n-type MOS device (NMOS) channels and to increase movement of holes (carriers) in p-type MOS device (PMOS) channels. Fin-based transistor devices can be used to provide improved short channel control. Typical CMOS transistor devices utilize silicon as the channel material for both hole and electron majority carrier MOS channels. Switching to other channel materials can improve mobility. For example, an indium-rich indium gallium arsenide (InGaAs) in an NMOS channel on a gallium arsenide (GaAs) sub-fin produces high-mobility and better performance NMOS transistors, relative to conventional silicon NMOS transistors. However, there are a number of non-trivial issues associated with indium-rich NMOS channels.
As will be appreciated, the figures are not necessarily drawn to scale or intended to limit the present disclosure to the specific configurations shown. For instance, while some figures generally indicate perfectly straight lines, right angles, and smooth surfaces, an actual implementation of an integrated circuit structure may have less than perfect straight lines, right angles, and some features may have surface topology or otherwise be non-smooth, given real world limitations of the processing equipment and techniques used. In short, the figures are provided merely to show example structures.